This project is to develop and evaluate the potential of gastrointestinal endoscopic optical fiber fluorimetry (GEOFF) sensors which are disposable and cost effective. These sensor devices (medical optrodes) are expected to be used to measure fluorscence from tissues in vivo using dyes such as rhodamine 123, a mitochondrial specific dye. In addition, these sensors are to be used to assist in the development of a first generation of endoscopic devices which are programmed with special functions such as detection, recognition, storage, and comparison of tissue data obtained from spectral cues.